Core A. Clinical examines the natural history of senile dementia of the Alzheimer type (SDAT) and healthy aging in longitudinal samples of carefully assessed subjects, using established clinical, cognitive, and neurological methods. The Core also recruits, evaluates, and supplies subjects to the individual projects in this renewal application. Clinicopathological correlations are enhanced by the Core's emphasis on obtaining autopsy permission from both nondemented and demented subjects. Data from these Core activities are compared, with the assistance of Core D. Biostatistics, with those from Core B. Psychometrics, Core C. Neuropathology, and all Projects to explore the central theme of the Program Project: the behavioral and biomedical correlates of SDAT in comparison with healthy aging. These objectives build on our previous studies in these areas. The study of very old persons (aged 80 years and over) will be expanded by enrolling additional subjects and serially assessing them until autopsy to examine areas of overlap in advanced aging and Alzheimer's disease. Core clinical data, including information obtained by a Retrospective Collateral Dementia Interview in brains obtained from the Body Donor Program or General Autopsy Service, will be correlated with detailed patho-anatomic mapping of markers of neuronal degeneration. Attentional factor affecting memory processing in aging and dementia and the effects of hypoglycemia on memory performance will be studied in Core subjects. The Core will continue to enroll subjects in the very mild stages of SDAT and follow its established samples of subjects, originally entered as controls, to distinguish the earliest clinical manifestations of disease from changes associated with aging and to identify those factors predictive of SDAT.